Suggestion: ignore linters due to imported functions

[ThierryO]

Since there is no common coding style in R, importing functions from other packages often results in a clash of coding styles. Currently we have to #nolint the offending functions, which is a bit tedious. All imported functions are listed in NAMESPACE so that would be nice place to look for the exceptions.

[jimhester]

An alternative is to use :: or ::: to refer to functions they will automatically excluded from the object linters. This style is the recommended one in Hadley's R Packages book.

Excluding functions imported into the package NAMESPACE is possible of course, but lintr currently works on a file a time and does not handle package structure at all, so it would require some changes in how things work.

[fangly]

@ThierryO I like your suggestion!
@jimhester It would make sense if the lint_package function automatically dealt with the NAMESPACE and somehow added imported functions to the exclude function (although exclude currently only works on entire files and lines).

[ThierryO]

@jimhester Note that in the second paragraph Hadley writes:

If you are using functions repeatedly, you can avoid :: by importing the function with @importFrom pgk fun.

Would you accept a pull request which takes into account the imports from NAMESPACE? I'm willing to try implementing that.

[jimhester]

I think what @fangly Suggested makes sense, if the lint_package() parses the NAMESPACE file once they can then be added to the exclusion objects.

[fangly]

Come to think of it, if that's of the objects_linter.R (name length, camel case, etc) that we are talking about, there may be a better strategy. I do also get a lot of lints from function calls, dataframe accesses, etc that I did not create.
It seems like it would be preferable to lint only objects that are assigned, not just merely used or called. To illustrate this, in this example, we would only check the names of f, a, b and x:
f <- function(a, b) {x <- 1}
Likely, the "make_object_linter" function could be adapted for this purpose.

[fangly]

I updated my object_name_linter() to only lint assigned object, as described in my previous comment.

[fangly]

Fixed in #214